Experimental Physics and
Industrial Control System

Michael Davidsaver via Tech-talk <tech-talk at aps.anl.gov> · Thu, 31 Mar 2022 14:10:34 -0700

On 3/31/22 01:50, Florian Feldbauer wrote:

...

$ cat configure/os/CONFIG.linux-arm.linux-arm
# CONFIG.linux-arm.linux-arm
#
# Definitions for native linux-arm builds
# Sites may override these definitions in CONFIG_SITE.linux-arm.linux-arm
#-------------------------------------------------------

# Include common gnu compiler definitions
include $(CONFIG)/CONFIG.gnuCommon
$ cat configure/os/CONFIG.linux-x86.linux-x86
#  CONFIG.linux-x86.linux-x86
#
# Definitions for linux-x86 host - linux-x86 target builds
# Sites may override these definitions in CONFIG_SITE.linux-x86.linux-x86
#-------------------------------------------------------

# Include common gnu compiler definitions
include $(CONFIG)/CONFIG.gnuCommon

STATIC_LDFLAGS_YES= -Wl,-Bstatic
STATIC_LDFLAGS_NO=
STATIC_LDLIBS_YES= -Wl,-Bdynamic
STATIC_LDLIBS_NO=

Adding those 4 last rows from CONFIG_SITE.linux-x86.linux-x86 to CONFIG_SITE.linux-arm.linux-arm solved my issue.
Now static build also works on armv7.

I think you are correct that passing both '-static' and '-Wl,-Bdynamic'
is a contradiction, which GCC unfortunately does not flag as an error.

Do you want to formulate this change as a pull request?

https://github.com/epics-base/epics-base/

I can't see exactly where, but "/lib/ld.so.1" must be used as a default
when no "-dynamic-linker ..." is passed to "ld".  The valid values
for ARM are given here:

https://github.com/gcc-mirror/gcc/blob/0abc1cbad1687a887d754917927b6023e4dba3ce/gcc/config/arm/linux-eabi.h#L59-L65

fyi. these names actually appears in GCC's generated spec file(s), where
it can presumably be overwritten, if you understand spec files better than
I do...

https://gcc.gnu.org/onlinedocs/gcc/Spec-Files.html

gcc -dumpspecs|grep dynamic-linker

As I understand it, on amd64 it looks like all of the "-dynamic-linker ..."
are wrapped in a conditional "%{!static: ...}".  So '-static' prevents
any from being passed to "ld".

Cheers,
Florian

Alternately, you could path Base to remove references to "-Wl,-Bdynamic",
which would result in a fully static executable (with the limitations
which this implies).

/usr/bin/g++ -o antelope -static -L/epics/base/lib/linux-arm -Wl,-rpath,/epics/base/lib/linux-arm          -rdynamic closure.o error.o lalr.o lr0.o antelope.o mkpar.o output.o reader.o skeleton.o symtab.o verbose.o warshall.o -Wl,-Bdynamic  -lpthread   -lreadline -lm -lrt -ldl -lgcc

However, you may later encounter strange linker errors and/or crashes
if object code from different, somewhat incompatible, toolchains are
being linked together.  So I would encourage you to investigate the
toolchain(s) first.

Cheers,
Florian

Am 30.03.2022 um 17:47 schrieb Michael Davidsaver:

On 3/30/22 07:15, Florian Feldbauer via Tech-talk wrote:

Hey all,

we use docker images to easily deploy our IOCs for our detector control system.
The images are build for amd64, arm64/aarch64 and armv7.

To reduce the size of those images, I recently switched from dynamic to static linking by adding the line
 >      && echo "STATIC_BUILD=YES" >> configure/CONFIG_SITE.local \
to our Dockerfile.

When compiling base7 for amd64 and aarch64 this is working just fine, but I get an error on arm/v7:

#0 189.7 Installing created executable /epics/base/bin/linux-arm/antelope
#0 190.1 /epics/base/bin/linux-arm/antelope -bparse -l -d ../flex/parse.y
#0 190.1 /usr/lib/ld.so.1: No such file or directory
#0 198.7 Expanding ../libComVersion.h@ to ../O.Common/libComVersion.h

I investigated the issue a bit closer and found the following:

root@195e454a8580:/epics/src/base# ldd /epics/base/bin/linux-arm/antelope
  linux-vdso.so.1 (0x7ef10000)
  libc.so.6 => /lib/arm-linux-gnueabihf/libc.so.6 (0x76e71000)
  /usr/lib/ld.so.1 => /lib/ld-linux-armhf.so.3 (0x76f70000)

It looks like "STATIC_BUILD=YES" was ignored.

root@195e454a8580:/epics/src/base# ls /usr/lib/ld.so.1
ls: cannot access '/usr/lib/ld.so.1': No such file or directory

For some reason antelope gets linked against /usr/lib/ld.so.1 on armv7 but this file does not exist.
Does anyone know what causes this issue?

It would help if you could attach, or post somewhat, the complete
output of a clean 'make'.

Also the output of:

readelf -aW /epics/base/bin/linux-arm/antelope

Cheers,
Florian

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System